Small objects such as screws, bolts, washers and o-rings are an essential part of keeping machinery running and repaired. O-rings, for example, frequently consume a very large and disproportionate amount of space relative to their value. Furthermore, disorganized storage of the o-rings frequently requires significant time and effort to find the needed size and compound. Machinery downtime and lost production are a direct result of the usual searches for proper o-rings. For example, lost repair labor is endemic as a result of regular and frequent searches for o-rings. Installation of mis-identified o-rings cause untold machinery failure, loss of production and occasionally loss of human life.
Because o-rings possess a multitude of attributes, not all of which may be critical to a specific sealing application, there is a great deal of confusion surrounding the process for selecting proper o-rings. Factors that are considered in the selection process include size, application, and elastomer composition of o-rings. The size characteristics of an o-ring include nominal size v. actual size, inside diameter (ID) and cross section (c/s) or wall thickness of the o-ring.
Application characteristics of an o-ring include matching the use of the o-ring with the most favorable, desired or required elastomer characteristics and composition. Uses include, for example, use as a gasket (static seal), use as a shaft seal (dynamic seal), use as a reciprocating seal (dynamic seal), and use as a hydraulic seal (high pressure seal).
Elastomer composition characteristics of an o-ring determine other attributes of the o-ring. The attributes include, for example, durometer (shore "A" scale for elastomer hardness), temperature (high and low limits), chemical resistivity to product and cleaning solutions, abrasion resistance to sliding or turning action, and compression set resistance (recovery from load deformation and/or temperature).
Another issue that is considered in the selection process is the environment and space in which o-rings are used. For example, edges must be radiused, clearance must be within tolerances, the space must be checked for burrs, dings, corrosion and any space non-conformance.
A further issue that is considered is the storage of o-rings to keep the o-rings protected. Elastomeric o-rings deteriorate more rapidly when exposed to daylight (UV). Additionally, they outgas (give off an odor) when not enclosed in an airtight storage container. Shop grime also shortens the functional life of o-rings. Elastomers have various shelf lives, but all deteriorate with time.
Finally, a further issue that is considered is identification and organization of o-rings. The United States managed to convene a large body of design engineers, and they agreed to a uniform system of identifying and organizing o-rings by assigning a three-digit number to each inside diameter (ID) permutated by each cross-section (c/s). This system is known as Aerospace Recommended Practice (APP) Universal Dash Series, and more recently is simply known as the AS (Aerospace Standard) 568A (Amended) published by SAE (Society of Automotive Engineers).
O-rings and the grooves they fit into vary by thousandths of an inch in size depending on their application. There are five (5) standard cross sections, one hundred and nineteen (119) inside diameters, and three hundred and forty-nine (349) o-ring size (ID.times.c/s) combinations. O-rings are ordered according to a "nominal size" of the o-ring. However, when measured, the "actual size" has a smaller inside diameter (ID) and the cross section (c/s) is larger than the "nominal size". For example, 1" nominal inside diameter (ID) of an o-ring would actually measure 0.984", and 1/8" nominal cross section (C/S) would actually measure 0.139". These differences provide the "squeeze" necessary for an o-ring to "work" properly.
In the past, o-rings have been organized in a kit with 30 sizes divided into 4 cross sections 1/16", 3/32", 1/8" and 3/16". The method of organization in the prior kit often provided as few as 3 inside diameter (ID) sizes having a 3/16" cross section size to as many as 13 ID sizes having the 1/8" cross section size. Although the prior o-ring kits provided a useful way of organizing o-rings, the choices of o-rings were extremely limited and the kit frequently did not have the o-ring needed for a particular application. The prior kits also did not have sufficient safe-guards to prevent an o-ring stock-out, nor did they have tools and information needed to identify, select and install the o-rings.
Accordingly, what is needed is an object storage, organization and selection system which provides the maximum choices in the minimum amount of space, which can stratify and organize o-rings so as to relieve anxiety and stress about o-rings and o-ring selection, and which makes the entire process concerning o-ring selection and storage more user-friendly.